California Code, Code of Civil Procedure - CCP § 410.50

(a) Except as otherwise provided by statute, the court in which an action is pending has jurisdiction over a party from the time summons is served on him as provided by Chapter 4 (commencing with Section 413.10).  A general appearance by a party is equivalent to personal service of summons on such party.

(b) Jurisdiction of the court over the parties and the subject matter of an action continues throughout subsequent proceedings in the action.